c++ - What does it mean to be "terminated by a zero"?

Question

I am getting into C/C++ and a lot of terms are popping up unfamiliar to me. One of them is a variable or pointer that is terminated by a zero. What does it mean for a space in memory to be terminated by a zero?

Answer 1

Take the string Hi in ASCII. Its simplest representation in memory is two bytes:

0x48
0x69

But where does that piece of memory end? Unless you're also prepared to pass around the number of bytes in the string, you don't know - pieces of memory don't intrinsically have a length.

So C has a standard that strings end with a zero byte, also known as a NUL character:

0x48
0x69
0x00

The string is now unambiguously two characters long, because there are two characters before the NUL.